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1 /*
2  * This program is free software; you can redistribute it and/or modify
3  * it under the terms of the GNU General Public License, version 2, as
4  * published by the Free Software Foundation.
5  *
6  * This program is distributed in the hope that it will be useful,
7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
9  * GNU General Public License for more details.
10  *
11  * You should have received a copy of the GNU General Public License
12  * along with this program; if not, write to the Free Software
13  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
14  *
15  * Copyright IBM Corp. 2007
16  * Copyright 2011 Freescale Semiconductor, Inc.
17  *
18  * Authors: Hollis Blanchard <hollisb@us.ibm.com>
19  */
20 
21 #include <linux/jiffies.h>
22 #include <linux/hrtimer.h>
23 #include <linux/types.h>
24 #include <linux/string.h>
25 #include <linux/kvm_host.h>
26 #include <linux/clockchips.h>
27 
28 #include <asm/reg.h>
29 #include <asm/time.h>
30 #include <asm/byteorder.h>
31 #include <asm/kvm_ppc.h>
32 #include <asm/disassemble.h>
33 #include <asm/ppc-opcode.h>
34 #include "timing.h"
35 #include "trace.h"
36 
kvmppc_emulate_dec(struct kvm_vcpu * vcpu)37 void kvmppc_emulate_dec(struct kvm_vcpu *vcpu)
38 {
39 	unsigned long dec_nsec;
40 	unsigned long long dec_time;
41 
42 	pr_debug("mtDEC: %x\n", vcpu->arch.dec);
43 	hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
44 
45 #ifdef CONFIG_PPC_BOOK3S
46 	/* mtdec lowers the interrupt line when positive. */
47 	kvmppc_core_dequeue_dec(vcpu);
48 
49 	/* POWER4+ triggers a dec interrupt if the value is < 0 */
50 	if (vcpu->arch.dec & 0x80000000) {
51 		kvmppc_core_queue_dec(vcpu);
52 		return;
53 	}
54 #endif
55 
56 #ifdef CONFIG_BOOKE
57 	/* On BOOKE, DEC = 0 is as good as decrementer not enabled */
58 	if (vcpu->arch.dec == 0)
59 		return;
60 #endif
61 
62 	/*
63 	 * The decrementer ticks at the same rate as the timebase, so
64 	 * that's how we convert the guest DEC value to the number of
65 	 * host ticks.
66 	 */
67 
68 	dec_time = vcpu->arch.dec;
69 	/*
70 	 * Guest timebase ticks at the same frequency as host decrementer.
71 	 * So use the host decrementer calculations for decrementer emulation.
72 	 */
73 	dec_time = dec_time << decrementer_clockevent.shift;
74 	do_div(dec_time, decrementer_clockevent.mult);
75 	dec_nsec = do_div(dec_time, NSEC_PER_SEC);
76 	hrtimer_start(&vcpu->arch.dec_timer,
77 		ktime_set(dec_time, dec_nsec), HRTIMER_MODE_REL);
78 	vcpu->arch.dec_jiffies = get_tb();
79 }
80 
kvmppc_get_dec(struct kvm_vcpu * vcpu,u64 tb)81 u32 kvmppc_get_dec(struct kvm_vcpu *vcpu, u64 tb)
82 {
83 	u64 jd = tb - vcpu->arch.dec_jiffies;
84 
85 #ifdef CONFIG_BOOKE
86 	if (vcpu->arch.dec < jd)
87 		return 0;
88 #endif
89 
90 	return vcpu->arch.dec - jd;
91 }
92 
kvmppc_emulate_mtspr(struct kvm_vcpu * vcpu,int sprn,int rs)93 static int kvmppc_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, int rs)
94 {
95 	enum emulation_result emulated = EMULATE_DONE;
96 	ulong spr_val = kvmppc_get_gpr(vcpu, rs);
97 
98 	switch (sprn) {
99 	case SPRN_SRR0:
100 		kvmppc_set_srr0(vcpu, spr_val);
101 		break;
102 	case SPRN_SRR1:
103 		kvmppc_set_srr1(vcpu, spr_val);
104 		break;
105 
106 	/* XXX We need to context-switch the timebase for
107 	 * watchdog and FIT. */
108 	case SPRN_TBWL: break;
109 	case SPRN_TBWU: break;
110 
111 	case SPRN_DEC:
112 		vcpu->arch.dec = spr_val;
113 		kvmppc_emulate_dec(vcpu);
114 		break;
115 
116 	case SPRN_SPRG0:
117 		kvmppc_set_sprg0(vcpu, spr_val);
118 		break;
119 	case SPRN_SPRG1:
120 		kvmppc_set_sprg1(vcpu, spr_val);
121 		break;
122 	case SPRN_SPRG2:
123 		kvmppc_set_sprg2(vcpu, spr_val);
124 		break;
125 	case SPRN_SPRG3:
126 		kvmppc_set_sprg3(vcpu, spr_val);
127 		break;
128 
129 	/* PIR can legally be written, but we ignore it */
130 	case SPRN_PIR: break;
131 
132 	default:
133 		emulated = vcpu->kvm->arch.kvm_ops->emulate_mtspr(vcpu, sprn,
134 								  spr_val);
135 		if (emulated == EMULATE_FAIL)
136 			printk(KERN_INFO "mtspr: unknown spr "
137 				"0x%x\n", sprn);
138 		break;
139 	}
140 
141 	kvmppc_set_exit_type(vcpu, EMULATED_MTSPR_EXITS);
142 
143 	return emulated;
144 }
145 
kvmppc_emulate_mfspr(struct kvm_vcpu * vcpu,int sprn,int rt)146 static int kvmppc_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, int rt)
147 {
148 	enum emulation_result emulated = EMULATE_DONE;
149 	ulong spr_val = 0;
150 
151 	switch (sprn) {
152 	case SPRN_SRR0:
153 		spr_val = kvmppc_get_srr0(vcpu);
154 		break;
155 	case SPRN_SRR1:
156 		spr_val = kvmppc_get_srr1(vcpu);
157 		break;
158 	case SPRN_PVR:
159 		spr_val = vcpu->arch.pvr;
160 		break;
161 	case SPRN_PIR:
162 		spr_val = vcpu->vcpu_id;
163 		break;
164 
165 	/* Note: mftb and TBRL/TBWL are user-accessible, so
166 	 * the guest can always access the real TB anyways.
167 	 * In fact, we probably will never see these traps. */
168 	case SPRN_TBWL:
169 		spr_val = get_tb() >> 32;
170 		break;
171 	case SPRN_TBWU:
172 		spr_val = get_tb();
173 		break;
174 
175 	case SPRN_SPRG0:
176 		spr_val = kvmppc_get_sprg0(vcpu);
177 		break;
178 	case SPRN_SPRG1:
179 		spr_val = kvmppc_get_sprg1(vcpu);
180 		break;
181 	case SPRN_SPRG2:
182 		spr_val = kvmppc_get_sprg2(vcpu);
183 		break;
184 	case SPRN_SPRG3:
185 		spr_val = kvmppc_get_sprg3(vcpu);
186 		break;
187 	/* Note: SPRG4-7 are user-readable, so we don't get
188 	 * a trap. */
189 
190 	case SPRN_DEC:
191 		spr_val = kvmppc_get_dec(vcpu, get_tb());
192 		break;
193 	default:
194 		emulated = vcpu->kvm->arch.kvm_ops->emulate_mfspr(vcpu, sprn,
195 								  &spr_val);
196 		if (unlikely(emulated == EMULATE_FAIL)) {
197 			printk(KERN_INFO "mfspr: unknown spr "
198 				"0x%x\n", sprn);
199 		}
200 		break;
201 	}
202 
203 	if (emulated == EMULATE_DONE)
204 		kvmppc_set_gpr(vcpu, rt, spr_val);
205 	kvmppc_set_exit_type(vcpu, EMULATED_MFSPR_EXITS);
206 
207 	return emulated;
208 }
209 
210 /* XXX Should probably auto-generate instruction decoding for a particular core
211  * from opcode tables in the future. */
kvmppc_emulate_instruction(struct kvm_run * run,struct kvm_vcpu * vcpu)212 int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
213 {
214 	u32 inst;
215 	int rs, rt, sprn;
216 	enum emulation_result emulated;
217 	int advance = 1;
218 
219 	/* this default type might be overwritten by subcategories */
220 	kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
221 
222 	emulated = kvmppc_get_last_inst(vcpu, INST_GENERIC, &inst);
223 	if (emulated != EMULATE_DONE)
224 		return emulated;
225 
226 	pr_debug("Emulating opcode %d / %d\n", get_op(inst), get_xop(inst));
227 
228 	rs = get_rs(inst);
229 	rt = get_rt(inst);
230 	sprn = get_sprn(inst);
231 
232 	switch (get_op(inst)) {
233 	case OP_TRAP:
234 #ifdef CONFIG_PPC_BOOK3S
235 	case OP_TRAP_64:
236 		kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
237 #else
238 		kvmppc_core_queue_program(vcpu,
239 					  vcpu->arch.shared->esr | ESR_PTR);
240 #endif
241 		advance = 0;
242 		break;
243 
244 	case 31:
245 		switch (get_xop(inst)) {
246 
247 		case OP_31_XOP_TRAP:
248 #ifdef CONFIG_64BIT
249 		case OP_31_XOP_TRAP_64:
250 #endif
251 #ifdef CONFIG_PPC_BOOK3S
252 			kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
253 #else
254 			kvmppc_core_queue_program(vcpu,
255 					vcpu->arch.shared->esr | ESR_PTR);
256 #endif
257 			advance = 0;
258 			break;
259 
260 		case OP_31_XOP_MFSPR:
261 			emulated = kvmppc_emulate_mfspr(vcpu, sprn, rt);
262 			break;
263 
264 		case OP_31_XOP_MTSPR:
265 			emulated = kvmppc_emulate_mtspr(vcpu, sprn, rs);
266 			break;
267 
268 		case OP_31_XOP_TLBSYNC:
269 			break;
270 
271 		default:
272 			/* Attempt core-specific emulation below. */
273 			emulated = EMULATE_FAIL;
274 		}
275 		break;
276 
277 	case 0:
278 		/*
279 		 * Instruction with primary opcode 0. Based on PowerISA
280 		 * these are illegal instructions.
281 		 */
282 		if (inst == KVMPPC_INST_SW_BREAKPOINT) {
283 			run->exit_reason = KVM_EXIT_DEBUG;
284 			run->debug.arch.address = kvmppc_get_pc(vcpu);
285 			emulated = EMULATE_EXIT_USER;
286 			advance = 0;
287 		} else
288 			emulated = EMULATE_FAIL;
289 
290 		break;
291 
292 	default:
293 		emulated = EMULATE_FAIL;
294 	}
295 
296 	if (emulated == EMULATE_FAIL) {
297 		emulated = vcpu->kvm->arch.kvm_ops->emulate_op(run, vcpu, inst,
298 							       &advance);
299 		if (emulated == EMULATE_AGAIN) {
300 			advance = 0;
301 		} else if (emulated == EMULATE_FAIL) {
302 			advance = 0;
303 			printk(KERN_ERR "Couldn't emulate instruction 0x%08x "
304 			       "(op %d xop %d)\n", inst, get_op(inst), get_xop(inst));
305 		}
306 	}
307 
308 	trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);
309 
310 	/* Advance past emulated instruction. */
311 	if (advance)
312 		kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
313 
314 	return emulated;
315 }
316 EXPORT_SYMBOL_GPL(kvmppc_emulate_instruction);
317